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How to work locks

As a boater, how do I pass through a mechanised or automatic lock?...


How to work locks

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Published on 27 May 2011 (updated on 9 June 2011)

Priority of passage through locks

Texte réglementaire Règlement Général de Police (decree of 21 September 1973) and specific regulations and bye-laws for the Canal des Deux Mers, 1st July 1985

Priority of passage through locks is given, in order:

  1. to work boats and floating equipment belonging to the Waterway Authority, the fire brigade, police or customs navigating through the canal for urgent service requirements.
  2. to vessels carrying goods or passengers on a regular or programmed service, and supplied with authorisation to this effect signed by the director of the Waterway Authority.
  3. to other passenger vessels; however priority can only be granted to these vessels once they have reached the lock.
  4. to all other categories of boat, including hire craft, in the order of their arrival at the lock.

Notification of passage on demand
To pass through locks outside the normal operating hours (both recreational craft and professionals), advance notice of your intended passage is to be given to VNF.
This request is to be addressed to the subdivision closest to your point of departure before 15:00 on the eve of the day you wish to navigate. In particular, the request must be made on Friday for any passage on the Saturday, Sunday or Monday; and the eve of any public holiday for navigation on the public holiday or the day after.

Boat’s crew

The boat must be crewed by a minimum of 2 persons. The lock-keeper may have to refuse passage to a boat with only one person on board. The skipper must stay at the helm to handle the boat as necessary, while the crew member attends to the mooring lines and makes sure that the boat is properly tied up.

Instructions on tying up boats in the locks

Tying up and handling mooring lines are the responsibility of the boat’s skipper (article 6.28 of the overall waterway regulations, règlement général de police ).
However, the lock-keeper may assist in putting lines around the bollard (or other apparatus provided) if he feels it useful or necessary, and particularly in the following exceptional cases:

  • in case of danger, to assist in making the boat secure as quickly as possible,
  • to instruct the boater in the correct use of his mooring lines.

In case of serious imminent danger the lock-keeper may secure the lines himself, having first stopped the lock operating cycle.

As a boater, how do I pass through a lock?

See "Working through locks", a sequence from VNF’s film "Navigating on the Canal des Deux Mers".

When you reach a lock, do not approach to less than 50m from the lock. Do not proceed until the green light shows, or you are invited to do so by the lock-keeper.

Come into the bank or moor to the pontoon or landing stage before the lock, to disembark one of your crew, who continues to the lock on foot to tie up the boat. The skipper must stay on board throughout the locking operation.

When approaching locks, you are asked to exercise all due caution, and to pay particular attention to children, who are not to take part in the lock operation. Under no circumstances is the lock to be used as an opportunity to take a break and remain tied up.

As soon as the gates ahead of you are opened, proceed slowly out of the lock.
Beware! On the Canal de Garonne there is a strong cross-current immediately downstream of the locks (especially in Haute-Garonne) which may cause your boat to drift suddenly

Once inside the lock:

Keeping the boat tightly moored while locking through is the skipper’s responsibility. The lock-keeper’s task is to check the safety of navigation and ensure that locking operations are effected normally. Consult the page devoted to the profession of lock-keeper

In the lock chamber, do not proceed beyod the mark painted on the lock wall.

The boat must obligatorily be tied up and the engine in neutral. Crew must not use the safety ladders set into the lock walls for disembarking , even when the purpose is to tie up the boat. Mooring must take into account the variation in water level as the lock fills or empties. Ropes must be allowed to slip smoothly round the bollards. Never tie a knot! Ropes must never be looped around the body or held at arms’ length, but must be correctly coiled down to avoid the risk of falling into the lock.

To ensure smooth navigation and save water, the lock-keeper may - depending on the traffic - wait to fill the lock with several boats at a time. Tie up your boat taking all due precautions with regard to the other boats. Be attentive and courteous.

The lock cycle starts...

Keep the ropes tight but free to slip round the bollards while the lock is filled or emptied.

Warning: at certain locks, the flow pattern on filling can produce violent cross-currents which may cause the boat to drift sideways across the lock. The crew on board must be sure to hold the mooring lines tightly at all times

When the gates open, proceed slowly out of the lock and come into the bank to pick up the crew member. Do not use the safety ladders set into the lock walls to re-embark on the boat!


The lock-keeper may be required to operate several structures, and in this case may not be present when you reach the lock.Please be patient, and thank you for your understanding!

On certain sectors and for optimising staff rosters from March to May and from September to November, or throughout the canal during the low season, boats may be accompanied by a mobile lock-keeper, boats being grouped by 2 or 3 for this purpose, to proceed through a series of locks: this is accompanied locking.

With a view to saving water, whenever possible, boats may be asked to lock through in groups.

During periods of drought, a notice to navigators fixes the statutory waiting time and the requirement to group boats for locking.
In normal operating conditions, a delay of 20 minutes may be imposed.

Locking through a mechanised or automated lock...

1 - Mechanised locks

Passage through locks is under supervision of a lock-keeper. Once the boat is tied up, the lock-keeper closes the gates behind the boat and starts the lock cycle. Follow his instructions or recommendations.

2 - Automatic locks

In automatic locks, the locking operations are controlled directly by the users by activating a rod suspended above the water or through a remote control. There are no duty lock-keepers. In case of an incident or emergency, the ‘emergency stop’ button should be pressed to stop the lock operation and alert the VNF staff member responsible for the sector, who will immediately come to the lock to give assistance.

How do I pass through an automated lock?

On the Canal de Garonne:

The locks are automated between Toulouse and Castets-en-Dorthe. Lock operation is controlled by a pole suspended above the middle of the canal.

Approach the control rod at reduced speed. Give the rod a quarter turn to the right ; you will see the orange flashing light, which means that your request to lock through has been registered.

The display with the lower red and the green light means that the lock is being prepared. When the gates are open, only the single green light is displayed. You may then proceed to enter the lock.
Warning: between locks 32 (Le Noble) and 53 (l’Embouchure), if the flashing orange light does not show when you have activated the rod, it means that the lock is already in use. Wait until the boat comes out of the lock and reactivate the rod.

Manœuvring inside the lock:

  1. Once you have tied up, pull on the rod or press the button to the right of the control cabin to close the lock-gates.
  2. When the water levels are equal, don’t forget to activate the control a second time to open the gates ahead of you.
  3. When the gates are open proceed cautiously out of the lock.
    If two red lights show, the lock is in default. Disembark and ask for assistance by pressing on the emergency call button. You will then be able to talk directly with a VNF staff member.

On the Canal du Midi :

With the exception of the automated section between Béarnais lock and Bayard lock, in the centre of Toulouse, the locks are mechanised and exclusively operated by the lock-keeper on duty at the structure or accompanying boats through a series of locks.

On the Junction Canal and the Canal de la Robine :

All the locks are automated and operation is controlled by pushing a button on the control unit. The only exception is Moussoulens lock on the Canal de la Robine.
The system for working these automated locks is based on a control unit on the lock side; instructions are given on the information panels installed on site.
The user first presses the button indicating the direction of navigation. A member of the crew must obligatorily remain on the lockside to supervise lock operation. If any problem occurs, press the red button to stop the lock operating cycle.